One friend of mine used to have a referees whistle by the phone which he blew enthusiastically once he realised it was a scam call, he hoped the burst eardrum they should have suffered would stop them in the future.

A work colleague used to get a weekly phone call asking for the winning lottery numbers. Despite telling the person (who was obviously ringing the wrong number) that he could not help he eventually gave up and joined in the fun. He asked them what their first number was and confirmed it had been drawn, carried on with all 6 and the bonus ball (think that's how it works - never paid the idiot tax myself) and confirmed that had all the numbers. He could hear shouting and screaming in the background, they probably had a very happy night and a very sad morning the next day.

But my question is, why do they all, without exception, have a south asian accent? Are they yet another phenomenon of the failure of the UK brand of 'multiculturalism'? .

I think they're in South Asia. Same reason as, when offshoring customer service was popular, you got South Asian accents. India has a decent number of suitably educated people and English is their second, and for many common, language.

I get the odd one with a West African accent - no doubt the same education and language thing applies in Nigeria and probably other countries.

The latest variant tell me, sometimes claiming to be Domestic and General, that the warranty on my washer/dishwasher or whatever is about to expire. Except for the boiler I have, given I'm now retired and have cash to spare, given up on such warranties.

Yes it's good fun winding them up, I do this occasionally if I've got the time. I think the longest is about ten mins before they realise that there are only so many rooms in the house where I need to check to find my glasses. I had one the other day who said that I might get a virus, to which I replied I've had my jab, so we had that for a bit before he hung up.

why do they all, without exception, have a south asian accent? Are they yet another phenomenon of the failure of the UK brand of 'multiculturalism'?

As they are from South Asia...